Unit B Section 1.2 Flashcards
melting
solid to liquid
freezing
liquid to solid
condensation
gas to liquid
evaporation
liquid to gas
deposition
gas to solid
sublimation
solid to gas
Properties are characteristics that can be used to describe a substance.
All matter has two types of properties:
Physical :
(Characteristics that can be noticed when the substance is alone ).
Chemical:
(Characteristics that can be seen when the substance interact with other substances)
List Physical Properties: (11)
- Colour
- Lustre
- Hardness
- Melting point
- Boiling point
- Ductility
- Malleability
- Conductivity
- Solubility
- Density
- Crystal shape
What happens when a substance goes under physical change?
its appearance or state may be altered, but its composition stays the same.
Melting point:
is the temperature at which it changes from a solid to a liquid.
- The melting point of ice is 0°C.
- table salt melts at 801°C
- propane melts at 190°C.
Boiling point
is the temperature at which its liquid phase changes to the gas phase.
- water’s boiling point is 100°C
- Table salt boils at 1413°C
- propane boils at 42°C.
Hardness
is a substance’s ability to resist being scratched
- Hardness is usually measured on the Mohs’ hardness scale from 1 to 10
- mineral talc is the softest substance
- Diamond is the hardest
Malleability
A substance that can be pounded or rolled into sheets is said to be malleable
- Aluminum foil
Ductility
Any solid that can be stretched into a long wire is said to be ductile
-Copper
Crystal shape
The shape of a substance’s crystals can help identify it.
- Salt crystals form cubes.
Solubility
is the ability of a substance to be dissolved in another.
- For example, sugar is soluble in
water, but cooking oil is not.
Density
is the amount of mass in a given volume of a substance.
- water is 1 g/mL
- gold is 19 g/cm3.
Conductivity
is the ability of a substance to conduct electricity or heat
A chemical property describes how a substance interacts with other substances such as acids
Chemical Properties :
- reaction with acids
- ability to burn
- reaction with water
- behavior in air
- reaction to heat
What is a chemical change?
A chemical change always results in the formation of a different substance or substances.
Ex. Pancakes
Pure substance:
A pure substance is made of only one kind of matter and has a unique set of properties that sets it apart from any other kind of matter
- maybe either an element or a compound.
- Examples: Mercury or sugar
element:
An element is a material that cannot be broken down into any simpler substance.
- basic building blocks for all compounds.
- elements are organized into a periodic table according to their properties.
- have their own symbols
compound:
When two or more elements combine chemically they form a compound.
Ex: hydrogen + oxygen = water
mixture:
A mixture is a combination of pure substances
- do not combine chemically as happens when a compound is formed. They remain in their original, pure form, even though they are not always easy to see distinctly once the mixture is made.
4 types of mixtures:
Mechanical mixtures, solutions, suspensions, colloids
mechanical mixture:
• In a mechanical mixture, the different substances that make up the mixture are visible. (hetergenous)
-Ex. Soil or veggie salad.
solution:
In a solution, the different substances that make it up are not separately visible (homogeneous)
Type of solutions
- Solid dissolved in liquid- sugar in coffee
- Liquid dissolved in liquid- acetic acid in water(vinegar)
- Gas dissolved in liquid- CO2 in water (carbonated pop)
- Gas dissolved in gas- oxygen in nitrogen (atmosphere)
- Solid dissolved in solid- copper in silver (sterling )
aqueous solution:
a substance dissolved in water
- freshwater or vinegar
suspension:
A suspension is a cloudy mixture in which tiny particles of one substance are held within another.
-separated with a filter
Ex. Tomato Juice
colloid:
A colloid is also a cloudy mixture, but the particles of the suspended substance are so small that they cannot be easily separated.
-Ex. milk and ketchup
